Abstract

Background

To our knowledge, no study reported so far has investigated appropriate vancomycin dosing, which is important for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection in Thai patients of various ages and with varying degrees of renal function.

Objectives

To predict vancomycin dosing for MRSA in Thai patients of various ages and with varying degrees of renal functions.

Methods

Monte Carlo simulation and minimal inhibitory concentration (MIC) distribution of MRSA from a hospital in Thailand were used to predict the area under the curve in 24 h/MIC >400 and trough concentration (Ctrough) <20 mg/L of 9 vancomycin dosage regimens for Thai patients stratified by age and renal function.

Results

Vancomycin dosing at least 2.5 g per day can attain cumulative fraction of response (CFR) of ≥90% in every age group. Vancomycin dosage achieving CFR of ≥90% for simulated patients with creatinine clearance (CLcr) was calculated using the Cockcroft–Gault equation. Appropriate vancomycin doses for Thai patients infected with MRSA with CLcr of <40, 40–60, >60–80, and >80 mL/min were 1.5 g every 24 h, 1.25 g every 12 h, 1 g every 8 h, and 1.75 g every 12 h, respectively. However, more than a half of patients simulated using these regimens have a vancomycin Ctrough of >20 mg/L.

Conclusions

Although vancomycin doses attaining a CFR of ≥90% can treat MRSA infection effectively, the regimens may cause kidney injury. The regimens have a probability of target attainment of 100%, and most patients can attain Ctrough of <20 mg/L.